Device for the parallel guidance of dental tools



y I K. A. s. KARLSTRGM 2,318,403

DEVICE FOR THE :PARALLEL GUIDANCE OF DENTAL TOOLS Filed Jan. 2, 1942 zsneets-sheet 1 @"M gggs.

1943-7 A. s. KARLSTROM 2,318,403

DEVICE FOR THE PARALLEL GUIDANCE OF DENTAL TOOLS Filed Jan. 2, 1942 2Sheets-Shea]; 2

95 mum mum 6 wwi gg ys Patented May 4, 1943 DEVICE FOR THE PARALLELGUIDANCE OF DENTAL TOOLS Karl Axel Sam Karlstriim, Gavle, SwedenApplication January 2, 1942, Serial No. 425,470 In Sweden February '7,1941 4 Claims. (01. 32-67) The present invention relates to thosedevices for the parallel guidance of dental tools Which are intended tobe placed in the mouth and in which a guiding sleeve for the tool iscarried by a support adapted to be fixed relatively to the teeth, and isswingably mounted around a pin running parallel to the axis of theguiding sleeve. Such devices have hitherto only been used for drillingmutually parallel pin holes which extend substantially in thelongitudinal direction of the tooth. The present invention contemplatesdrilling of holes which extend substantially at right angles to thelongitudinal direction of the tooth. The invention is characterizedsubstantially in that the pin carrying the guiding sleeve extendssubstantially at right angles to the longitudinal direction of theteeth, and is adjustable in different radial planes relatively to anaxis substantially parallel to the longitudinal direction of the teeth,and preferably also adjustable into different angular positions in eachradial plane. This makes possible an exact and convenient adjustment ofthe guiding sleeve and thus the tool to any desired position relativelyto the tooth.

The device may obviously also be used for guiding grinding tools inthose cases where grinding surfaces running substantially in thelongitudinal direction of the tooth are to be prepared.

The invention will be more fully described with reference to theaccompanying drawings, in which Figure 1 is a side view and Figure 2 aplan view of the device. Figure 3 is a cross section and Figure 4 a planview of the device on an enlarged scale. Figure 5 shows anotherembodiment of the device as seen from the side and partly in section.Figure 6 shows the device as seen from above. Figure '7 shows a part ofthe ball-and-socket joint as seen from above.

The device is intended to be fixed relatively to the teeth by means of aplastic mass 2 which is hard at ordinary temperatures and in which thesupport 4 is embedded and which is cast into the fore jaw portion, asshown in Figure l. The support consists of a V-shaped base plate 4having two inwardly directed legs 5, 6, the edges of which are waved, asshown in Figure 3 or otherwise shaped so as to hold the support firmlyin the casting mass 4. The support should be so arranged relatively tothe teeth that an upright 3 carrying the guiding sleeve and its pin willbe situated approximately in the centre of the are formed by the foreportion of the row of teeth. The upright 3 is connected to the plate 4by means of a ball-and-socket joint in such manner that it can be set indifferent inclined positions relatively to the support. Theball-andsocket joint consists of a semi-spherical member 8 riveted tothe plate 4, a calotteshaped member 9 connected to the upright 3 as wellas a bushing I0 embracing said two parts and having an inner bearingsurface concentric with the semi-spherical member 8. The bushing Ill issecured to the plate 4 by means of screws I I, by the tightening ofwhich the friction resistance in the ball-and-socket joint may be givena suitable value, so as to allow the upright 3 to be set in differentinclined positions against the action of the friction resistance andthen remain in the adjusted position, without the screws II having to befurther tightened.

The upright 3 is provided with a radially extending arm l2 which formsthe pivot pin carrying the guiding sleeve I3. The guiding sleeve isswingably mounted on the pin through the medium of a link arm I4, I5 anda nut I6 which is threaded on to the pin and by means of which the linkarm may be set at different distances from the teeth. By means of theball-and-socket joint the guiding sleeve can be set in the correctposition relatively to the tooth in which the pin holes are to bedrilled, so that the holes come into correct positions relatively to thelongitudinal and transverse directions of the tooth. To facilitate theresetting of the guiding sleeve in a previously adjusted position, theball-andsocket joint is provided with graduations, as shown in Figure 4.The graduations are arranged on the adjacent portions of members 9 andIII, the latter being provided with a graduation I! arranged round theedge of the central opening and consisting of radially disposed scalelines, while the visible part of member 9 is provided with scale linesin the form of a number of concentric circles I8 and preferably also oneor more radial scale lines I9. When the pivot pin I2 is to be reset in aposition previously occupied, the upright 3 is turned by means of thearm I2, until the scale line I9 comes opposite the desired scale line ofthe scale II, whereupon the upright is tilted forwards and backwards,until one of the circles I8 touches the inner edge of the scale II atone of the scale lines I9 lying in the radial plane of the pin I2. Bythe firstnamed setting the guiding sleeve or the drill is adjusted to adirection substantially perpendicular to the transverse direction of thetooth, while the lattter setting designs to adjust the direction of thedrill to the inclination of the tooth, so that the bore holes will besubstantially perpendicular to the longitudinal direction of the tooth.It is,

however, obvious that by this arrangement the drill may be given otherdirections relatively to the tooth. After the pivot pin l2 has beenadjusted in the desired manner to a certain tooth, several mutuallyparallel holes may be drilled in the tooth, in that the guiding sleevel3, thanks to the link arm 14, it may be parallelly displaced laterallyas well as upwards and downwards, without the position of the pin l2having to be altered.

The setting of the upright 3 in different positions of inclination mayalso be effected in another manner than by means of a ball-andsocketjoint. Thus, the upright may, by both its ends, be fixed in the supportand adapted tobe set in different angular positions relatively to saidsupport in the manner shown in the copending Patent application No.348,914 of July 31, 1940. The device described may also be modified insuch manner that the upright 3 is rigidly fixed in the support, whilethe pin I2 is pivotally connected to the upright in such a way that itmay be swung around the upright as well as given difierent positions ofinclination by being turned around an axis perpendicular to the upright;

In the embodiment shown in Figures 5 to 7, the pivot pin 2! forms, as inFigures 1 to 4, an arm extending radially from the upright 22 andrigidly connected to theupper endof the upright. The lower end 23 of theupright is semispherical in shape and fitted into a bushing 24 which issemi-spherical onthe inside and removably connected to the support 25,which, as in Figures 1 to 4, consists of a central plate 25 and two legs2B, 2? extending from said plate. The bushing 24 is conical on theoutside andkept fixed to the plate 25 by means of three lugs 23extending from said plate and embracing the lower edge of the bushing.In the assembly of the ball-and-socket joint the bushing 24 is firstplaced in such a position that a notch 29 made in the edge comesopposite one of the lugs 28, whereupon the bushing is locked by beingturned so that the notch 29 will be positioned between two lugs 28.

The upright 22 is in this embodiment tubular and threaded on to acentral pin 30 threaded into the lower semispherical part 23. The pin23, which is provided at its upper end with a head 3!, bears by itslower end against a pivot 32 riveted to the plate 25 and having asemispherical upper surface concentric with the bearing surface of theball-and-socket joint. After the upright 22 has been set in the desiredposition of inclination, the central pin 39 is turned by means of thehead 31, whereas the spherical surface of part 23 is kept in frictionalengage ment with the inner surface of the bushing 24. Part 23 will thenbe screwed on to the central pin 30 and pressed against the inner sideof the 1 bushing 24 so as to lock the upright in the adjusted position.To change the position of adjustment, the upright is loosened by turningthe pin 3% in the opposite direction. The guiding sleeve 36 is, as inFigures 1 to 4, swingably mounted by means of a double link 35, 36 onthe pivot pin 2i through the medium of a nut 31 which is threaded on tothe pin and by means of which the link arm and the guiding sleeve can beset at different distances from the teeth.

The pivot pin 2! and the centre pin 30 have preferably the same diameterand the same thread, so that they may alternatively be used as an axisof oscillation for the guiding sleeve. If e. g. it is desired to passfrom drilling transverse holes to drilling longitudinal holes, this maybe effected by removing the pivot pin 2| and the upright 22 from theball-and-socket joint and inserting instead a part corresponding to thesemi-spherical part 23, into which the centre pin 35) is threaded and bymeans of which the pin 30 may be locked in different angular positionsin the manner just described with reference to the upright 22. Thecentre pin'30, extending from the ball-and-socket joint, being now free,it may be used as an axis of oscillation for the guiding sleeve 34 andthe link arms 35,36, after the nut 31 has been threaded on to said pin.

The bushing may, as shown in Figure 7, be provided with a scale adaptedto be used together with scale lines or the like on part 23v for settingthe upright 22 or the pin 2| in fixed angular positions.

I claim:

1. Device for the parallel guidance of denta tools, in which a guidingsleeve for the tool is carried by a support adapted to be fixedrelatively to t .e teeth, and is swingably mounted around a pin runningparallel to the axis of the guiding sleeve, characterized in that thepin extends substantially at right angles to the longitudinal directionof the teeth, and is adjustable in different radial planes relatively toan axis substantially parallel to the longitudinal direction of theteeth, and preferably also adjustable into diiierent angular positionsin each radial plane.

2. Device as claimed in claim 1, characterized in that the pin iscarried by an upright which is substantially parallel to thelongitudinal direction of the teeth and adjustable into differentangular positions relatively to the support.

3. Device as claimed in claim 1 in which the pin is carried by anupright extending substantially at right angle to the pin and connectedto the support by means of a ball-and-socket joint.

4. Device as claimed in claim 1, in which the pin is carried by anupright extending substantially at right angle to the pin, said uprightbeing tubular and threaded on to a center pin adapted to be fixed indifferent angular positions relatively to the support.

KARL AXEL SAM KARLSTROM.

